In his campaign to win election to the U.S. Senate
in 1858, Abraham Lincoln of Illinois challenged
the incumbent, Senator Stephen A. Douglas, to a
series of seven debates, which took place throughout
the state between August 21 and October 15. These
Lincoln-Douglas debates centered on the question
of slavery and its expansion into the western states
and territories. While Lincoln adamantly opposed
its extension, Douglas defended his concept of popular
sovereignty, the doctrine of letting the settlers
decide for themselves the issue of slavery. Although
Lincoln would lose the election, he gained valuable
national exposure and showed himself to be a viable
political contender for future public office.

This ambrotype was taken of Lincoln in Monmouth
on October 11, 1858, two days before the next
to last debate with Douglas.